JPH02397A - Lead frame of substrate for loading electronic parts - Google Patents

Abstract

PURPOSE:To attain standardization while a part loading region is ensured widely by composing a lead frame of each lead and a frame framework supporting these leads respectively independently. CONSTITUTION:A plurality of mutually electrically independent leads 21 are projected from a wiring substrate 10. The wiring connecting sections of an electronic part 30 loaded onto the substrate 10 and each lead 21 are connected electrically by through-holes 12 formed brought into contact with respective lead 21. A lead frame 20 consists of each lead 21 and a frame framework 23 supporting these leads respectively separately. Consequently, an island section such as the lead frame is removed completely. Accordingly, standardization is attained while a part loading region is ensured widely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a lead frame for configuring a board for mounting electronic components, and in particular, the present invention relates to a lead frame for configuring a board for mounting electronic components, and in particular, a lead frame that protrudes from the base material and a connecting portion of an electronic component mounted on the base material. The present invention relates to a sheet frame suitable for configuring a board that is electrically connected to each lead.

(Prior Art) The high-density electronic components of recent years cannot be used to construct various electronic devices as they are.

This must be mounted on a board before use. To this end, various types of electronic component IT boards have been developed and proposed.

An example of a method for connecting electronic components and terminals for external connection such as leads on a board is to connect electronic components via a large number of conductor bins planted in a predetermined arrangement and a conductor circuit on the board. There are so-called PGAs to be connected, so-called TABs in which part of the conductor circuit on the 71 board is used as finger leads on which electronic components are directly mounted, and so-called DIPs in which the leads and electronic components are wire-bonded and the whole is molded. be.

Among these, for example, D has a plurality of electrically independent leads protruding from a base material, and each lead is electrically connected to the connection part of an electronic component mounted on this base material.
Taking an IR type board as an example, Japanese Patent Application Laid-Open No. 1986-1945
Various embodiments have been proposed in Publication No. 53 and the like.

What is proposed in JP-A No. 60-194553 and others is that ``a circuit board made of a material selected from silicone, polyimide, alumina, epoxy, and glass epoxy is attached to the island part of a metal base ribbon using an adhesive. A hybrid integrated circuit device is characterized in that a circuit board is bonded, a circuit board is mounted on the circuit board, and the circuit board is sealed with a resin.'' However, conventional electronic component mounting boards typified by such a hybrid integrated circuit device are There are mainly two basic configurations as shown in FIGS. 8 and 9. In other words, the first basic configuration is a metal material (consisting of a metal base ribbon) located in the part where the electronic component is mounted (island part), or multiple other parts that should become the REIT. is considered to be completely independent.

Also, is the second basic configuration related to the first basic configuration, or is the metal material located in the part where the electronic component is installed and the other parts that are to become leads mutually independent? Therefore, as shown in FIG. 9, the two must be wire-bonded.

The reason why conventional boards, in which the connecting parts of electronic components mounted on a base material and each lead are electrically connected, has to adopt the above basic configuration is that each lead is electrically independent. This is because each terminal of the electronic component must be separately and independently connected to each of these REETs. Also, for reasons of actual manufacturing, the two basic configurations described above seem to be adopted.

In other words, after the above-mentioned electronic component mounting board has been subjected to predetermined wire bonding, the entire board is sealed with a resin using so-called transfer molding, etc., but in this case, positioning of each lead becomes easier. must be maintained. For this purpose, as shown in Figure 8,
First, these leads and the metal material corresponding to the part (island part) on which electronic components are to be mounted are formed into a single metal plate (generally called a lead frame) using a frame. The configuration is such that the metal material located in the part where the electronic component is mounted and each lead can be placed on the same surface. Such a lead frame is manufactured by, for example, Japanese Utility Model No. 60-15874.
As shown in Publication No. 7 and FIG. 10, - In boat fishing, there are also those that are formed continuously horizontally or vertically.

(Problem to be solved by the invention) However, if the above-mentioned configuration is adopted for the board frame for configuring the board for mounting electronic components, it will not meet the requirements of various boards for mounting electronic components in recent years. When performing high-density packaging, the following problems arise that must be solved. In other words, ■Since each lead must be directly wire-bonded to the conductor circuit on the board to which electronic components are connected,
Not only does the entire electronic component have to be sealed with resin after it is mounted, but it is also necessary to extend the electrodes to the outer periphery of the island so that wire bonding can be done over short distances, which makes circuit design F difficult. There will be very little freedom.

Additionally, each REIT must be plated with gold or silver to ensure wire bonding.

■The metal material located in the part where electronic components are mounted (island part), that is, the metal type base ribbon located in the island part, is not used as a base for electronic parts, but it simply forms the part on which electronic parts are mounted. It is used for reinforcement and cannot be actively used as a wiring circuit. Therefore, the metal base ribbon located in the island portion is not suitable for high-density packaging. Moreover, the existence of this island portion not only makes it difficult to form through holes in this portion, but also limits the size of electronic components to be mounted on it, making it highly versatile. I can't do anything.

(2) Since the island portion where the electronic component is subjected to FT>a and the lead portion connected to the outside are separate and separate from each other, the only way to connect the two is by wire bonding. Therefore, not only is it difficult to perform high-density mounting, but it is also necessary to ensure reliability by using a resin M It: L/ for the bonding wire.

■If the above-mentioned island portion exists in the board, when the entire board on which electronic components are mounted is sealed by transfer molding, etc., the base material may peel off at this island portion as an interface. Cracks centered around this island portion tend to occur in the base material, and the reliability of the device mounted with electronic components decreases.

As a result of intensive research by the present inventors to solve the above problems, we have integrated each lead with a frame as a component of a board for mounting electronic components, and integrated internal connection parts inside each lead. The present invention was completed based on the new finding that good results can be obtained by using a lead frame which is formed as a lead frame and embedded in the base material constituting the substrate.

The purpose of the present invention is to solve the above-mentioned problems, reduce the restrictions on the size of electronic components to be mounted, provide excellent versatility, and prevent peeling and cracking in electronic component mounting boards. It is a lead frame that does not cause any problems.
It is provided by a simple structure.

(Means for Solving the Problems) The means taken by the present invention to solve the above problems are explained with reference to FIGS. 1 to 7 corresponding to the embodiments. A plurality of REITs (21) are made to protrude from the wiring board (10), and the wiring board (
An electronic component W in which the wiring connection portion of the electronic component (30) and each lead (21) formed on the top of the electronic component (1O) are electrically connected to each lead (21) by a through hole (12) formed in contact with each lead (21). ? A lead frame (20) constituting the board (010),
0) is constituted by each lead (21) and a frame (23) that supports each lead independently.

Below, the means taken by the lead frame (20) related to the final IJJ will be explained in detail according to the specific example shown in the drawings.

First, the lead frame (20) according to the present invention is formed by punching or etching a thin metal plate, as shown in FIGS. 1, 6, and 7. A plurality of leads (21) protruding toward the approximate center of the lead (20) are integrated by a frame (23) located on the outer periphery thereof.

This lead frame (20) has an internal connection part (22) integrally formed at the inner end of each lead (21).

This lead frame (20) is used to configure the electronic component mounting board (100) shown in FIG. The electronic component (30) is mounted on another large board or the like by means of leads (21) protruding from the wiring board (10). Then, this electronic component mounting board (100) is used as a lead frame (20) as described above.
1) or the wiring board (100) of the electronic component mounting board (100)
10) which integrally has an internal connection part (22) buried in the inside thereof. In other words, in this electronic component mounting board (ioo), the lead according to the present invention is constructed by integrally fixing a plurality of gates (21) having internal connection portions (22) with a frame (23). Of the REETs (21) that make up this lead frame (20) by adopting the frame (20)!
! 6. A base material made of a material such as resin or ceramic is integrally provided on both sides of the connection part (22), and at least a conductor circuit (11) for the electronic component (30) is formed on this base material. . Each conductor circuit (11) and each internal connection part (22) are electrically connected by a through hole (12).

As described above, various materials can be used as the base material of the electronic component mounting board (100) formed using the lead frame (20) as a constituent material. In other words, the materials for this base material include silicone, polyimide,
In addition to various resin ceramics such as alumina, epoxy, and glass epoxy, any material may be used as long as it has insulating properties and can be reliably attached to the metal internal connection part (22). In addition, this base material may be one made by laminating and integrating a plurality of materials, such as a lead frame (2
0) may be formed by a method such as printing. That is, each base material is simply a lead frame (20
) may be formed on both sides of the internal connection portion (22), but may also be formed as a multilayer structure, as shown in FIGS. 3 and 4, for example. Of course, if a multi-layered base material is used, conductor circuits (11) may be formed between each layer.

Similarly, various materials can be used to construct the lead frame (20). In other words, any metal may be used as long as it has the necessary conductivity, and not only copper alloy but also so-called 42 alloy is sufficient. In addition, these lead frames (20) may be used by bending the lead 1' (21) as shown in Figure 5, or may be used as so-called heat dissipation fins, so materials suitable for these are used. It is preferable to choose. In that sense, the most suitable lead frame (20) is one made mainly of copper.

In the electronic component mounting board (100) that employs this lead frame (20), each electronic component (30) mounted on it is mounted on each lead as shown in FIGS. 2 to 5. It is electrically connected to each REET (21) side by a through hole (12) formed by penetrating the internal connection part (22) of (21). Therefore, the electronic component (30) used in this electronic component mounting board (10G) may be of an insertion type such as a so-called dip type, or may be a molded surface mount component. ,'lf
No limitations are placed on the format of the child component (30). Furthermore, it is also possible to mount each electronic component (30) on both sides of this electronic component mounting board (100), and the size thereof is not limited either.

Of course, the frame frame (23) of the lead frame (20) according to the present invention is the first U.
It is discarded by cutting each lead (21) at a predetermined position as shown by the cutting line (25) of j1 or the virtual line in FIG. That is, the lead frame (
The frame frames (20) are mainly used for positioning each lead (21) until a certain point.
When the electronic component MS service board (100) is finally completed, it will no longer exist.

(Actions of the Invention) The lead frame (20) according to the present invention has the following effects by adopting the above measures.

■In the electronic component mounting board (100) that employs this lead frame (20), the conductor circuit (11) on the wiring board (10) to which the electronic component (30) is connected is connected to each lead (21). The conductor circuit (11) located on the wiring board (10) and the conductor circuit (11) located in the wiring board (10) that do not require direct wire bonding are:
Each internal connection (22) in the lead frame (20)
This is because the connection can be made through each through hole (12) that penetrates the. Therefore, it is not necessarily necessary to seal the entire wiring board (10) with resin after mounting the electronic components (30). Therefore, in the electronic component mounting board (100) that employs this lead frame (20), the conductor circuit (11) is drawn out near the island part in order to perform wire bonding over a short distance, like a conventional board. There is no need to keep it in place, and the degree of freedom in circuit design is extremely high. In addition, the conductor circuit (1
1), it is acceptable to connect this portion with the bonding wire (32).

Also, a wiring board (
10) Since it is not necessary to directly wire bond the upper conductor circuit (11) and each lead (21), this lead frame (20) has gold or silver plated for bonding on each lead (21), etc.・There is no need to apply ink.

■This lead frame (20) has electronic components (
It is no longer necessary to form a portion (island portion) where #30) is #5@. The part used as the base of the electronic component (30) can be replaced with another conductor circuit (11), and the strength is determined by the internal connection part (20) of the lead frame (20).
22) or the wiring board (10) itself.

(2) Heat from the electronic component (30) is easily dissipated to the outside via each lead (21). The internal connection part (22) of the lead frame (20) is embedded in the wiring board (10), and is also integrated with the wiring board (21) made of a material with excellent thermal conductivity. Since it protrudes to the outside of the substrate (10), it can be actively used as a heat dissipation member.

(2) Each conductor circuit (11) and the lead (21) are connected via each through hole (12), so the electrical reliability thereof is extremely high. Moreover, since it is possible to employ this through hole (12) for each internal connection part (22) of each lead (21), each electronic component (30)
It can sufficiently withstand even when a relatively large current is passed through it, and its range of use is much wider than that of conventional boards that are connected only by wire bonding using thin metal wires. be.

■Since each conductor circuit H) and the lead (21) can be connected via each through hole (12), it is sufficient to make the wiring board (lO) and conductor circuit (11) multilayer. = R function, electronic parts (3
0) can be freely changed in the structure of the part on which it is mounted. Therefore, this lead frame (20
), the electronic component mounting board (100) does not require any sealing IE format for the electronic components (30) to be mounted on it, and is fully capable of handling high-density mounting. is now possible.

(2) Since this lead frame (20) does not have an island portion at all unlike the conventional one, the electronic component mounting board (100)
It is a matter of course that no cracks occur in the 24 ft of base material centered on the island portion.

■The lead frame is determined only by the external size, leads, leads, and number of leads, and is not affected by wiring drawn on the wiring board or through holes, and can be standardized while securing a wide component mounting area, reducing costs. The delivery time is short.

(Example) Next, the lead frame (20) according to the present invention will be described in detail according to each example shown in the drawings.

Figure 1 shows a lead frame (
20). In this example,
A plurality of leads (21) are held together by a frame (23) by punching a thin copper plate, and each lead (21) has an internal connection part (22) at its inner end. They are each formed into one piece. Each internal connection part (22) has a through hole (
12) or to make this internal connection part (22) itself a conductive circuit, the diameter is larger than that of each lead (21).

When configuring an electronic component mounting board (10G) using this lead frame (20), FIGS.
As shown in Figure 5, the inner part of each lead (21) and its integral internal connection! The wiring board (10) is integrally fixed to both the front and back surfaces of (22).

Note that the electronic component mounting board (1) shown in Figures 2 to 5
00), the wiring board (lO
) are formed to have a multilayer structure, and conductor circuits (11) are formed not only on the surfaces of these base materials but also between each base material. In the electronic component mounting board (100) shown in FIG. It is shown that a leat (2) that is integral with the connecting portion (22) is projected to the outside of the wiring board (1 port). In addition, each REIT (21
) is bent at right angles to each internal connection part (22) in order to make the electronic component mounting board (100) a so-called dip type board for mounting on another large board, etc.

Further, in this electronic component mounting board (100), a dip-type electronic component (30) is soldered to the conductor circuit (11) on the upper side in the figure, and the conductor circuit on the lower side in the figure A surface mount type electronic component (30) is connected to the circuit (11) by soldering. In addition,
In this electronic component mounting board (+00), the base material was formed of glass epoxy resin.

In addition, in the electronic component mounting board (100) shown in FIG. 3, each internal connection part (22) of the lead frame (20) or the wiring board (10) is arranged so that they are located above and below each other. has been done. In other words, this electronic component mounting board (1
00) is formed using a plurality of lead frames (20) (two in this example) as shown in FIG. The vertical positions of the respective leads (21) protruding from each other are shifted from each other.

Embodiment 2 FIG. 6 shows a lead frame (
20). This lead frame (2
0) is formed using 42 alloy,
Of course, each lead (21) is integrally fixed by the frame (2 pieces), and also connected at the middle part of each lead (21) using a connecting part (24). In addition,
Each connecting portion (24) is cut off at the same time as the frame frame (23) is cut off.

Embodiment 3 FIG. 7 shows a lead frame (
A plan view of the lead frame (20) is shown.
Embodiment 0) is substantially the same as the second embodiment, except that the position of the internal connection part (22) formed at the inner end of each reat (21) is shifted back and forth in the cross-V direction. This is different from the example. In this case, a through hole (12) is formed at the position shown by the imaginary line in the figure.

In addition, the lead frame (2
0) may be formed singly to constitute one electronic component mounting board (100) as shown in Fig. 1, or may be formed in large numbers as shown in Fig. 1O showing a conventional example. In some cases, lead frames (20) are formed continuously.

(Effects of the Invention) As explained below, in the present invention, as exemplified in each of the above embodiments, "a plurality of mutually electrically independent leads (21) are made to protrude from the wiring board (10)." Along with this wiring board (
10) For electronic component mounting, the wiring connection portion of the electronic component (30) mounted on the top and each lead (21) are electrically connected by through holes (12) formed in contact with these leads (21). A lead frame (20) constituting a substrate (ioo).
) is composed of each lead (21) and a frame (23) that supports each lead independently. This makes it possible to provide a lead frame (20) with a simple structure that has fewer limitations, has excellent versatility, and does not cause peeling or cracks in the electronic component mounting board.

That is, the lead frame (20) according to the present invention does not have any island portion unlike the conventional lead frame (20).

The lead frame is not affected by the wiring or through holes drawn on the wiring board, and can be standardized while ensuring a wide area for mounting components.

In addition, unlike the island portion in the conventional lead frame (20), this lead frame (20) does not have a part that occupies a large area in the base material. Even when used in materials, it does not cause peeling or cracking of the base material.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a lead frame according to the first embodiment of the present invention, FIG. 2 is a perspective view of a board for mounting electronic components using this lead frame, and FIG. 3 is a plan view of this lead frame. 41A is a cross-sectional view showing another electronic component mounting board, and FIG. 5 is still another example of the electronic component mounting board. 6 and 7 are cross-sectional views showing the present invention.
and FIG. 7 is a plan view of a lead frame according to a third embodiment. Fig. 8 is a plan view of a conventional lead frame, Fig. 9 is a partial perspective view showing a state in which a board for mounting electronic components is constructed using this lead frame, and Fig. LO is another conventional example. FIG. Explanation of symbols: 10 ports...Electronic component mounting board, 10...Wiring board, 12...Through-hole J, 20...Lead frame, 21...Lead, 22... Internal connection, 23
...Frame frame, 24-...Connection part, 25-...Cut F
Fi&! . -L

Claims (1)

[Claims] A plurality of electrically independent leads protrude from a wiring board, and a wiring connection portion of an electronic component mounted on the wiring board is formed in contact with each lead. A lead frame constituting a board for mounting electronic components electrically connected by through-holes, the lead frame being composed of each of the leads and a frame that supports each of them independently. A lead frame for a board for mounting electronic components.